1. Field of the Invention
The present invention relates to a control of a headrest used in automotive seat, and particularly to method and device for controlling the displacement of the headrest between its use position for supporting the head of an occupant and non-use position where the headrest is at a location down below the view field another occupant.
2. Description of Prior Art
A headrest control is generally effected by an automatic switch to displace a headrest body between a use position where it supports the head of an occupant on the seat and a non-use position where it is lowered away from the view field of another occupant. In particular, the headrest on an assistant seat next to a driver seat, as such automatic control is applied, will be moved away from both view fields of the driver and rear-seat occupant.
In this kind of headrest control, an over-current detecting system is adopted for detecting presence of an object which hinders the displacement of the headrest, by means of detecting an over-current produced from the over-load sate of a motor. The system stops the drive of the motor in response to the over-current, thereby ceasing the displacement of the headrest and protecting the motor against damage and overheat.
However, coventionally, in such over-current case, the headrest is stopped as it is and just holds the object between itself and the seat back, which result in requiring the occupant to operate the automatic switch in order to move the headrest from the object, and remove it from between the headrest and adjacent part of the seat. Thus, the operation in such case is annoying, which is particularly the case for the rear-seat occupant who can not easily see and remove the object from the assistant seat.
Moreover, the conventional automatic switch is a one-touch type one which has a memory function to store a switch area being depressed "on", to permit automatical displacement of the headrest between the use and non-use positions by depressing on the relevant switch area at one time. This arises a disadvantageous aspect that an unintentional depress upon the switch will cause the headrest to move against the object if any and hold it, thus resulting in such over-load state of the motor, or give a damage to an occupant on the seat on which is provided the headrest.